Polarity reversing switch



A 1966 H. BRECHTEL ETAL 3,

POLARITY REVERSING SWITCH Filed June 15, 1964 FIG. 6

HANS BRECHTEL HOWARD L. KNUTSON SIDNEY D. LAPHAM LEWIS C. TOMPKINS I INVENTORS FIG. L- fi emk 135% A1" TORNEY United States Patent 3,265,846 POLARITY REVERSING SWITCH Hans Brechtel, Des Piaines, 11]., and Sidney D. Lapham, Martinez, Howard L. Knutson, San Carlos, and Lewis C. Tompkins, Lafayette, Califi, assignors to Electro- Coatings Inc., Emeryville, Calif, a corporation of Delaware Filed-June 15, 1964, Ser. No. 375,141

8 Claims. (Cl. 200158) This invention relates to a reversing switch and in particular to a polarity reversing switch suitable for use in an electroplating operation.

Nearly all electroplating processes require direct current power. Since line current is usually alternating, electroplating installations require suitable power supplies to transform the alternating current into direct current. One type of equipment which can accomplish this purpose, and which has become exceedingly popular in the last few years, primarily because of its relatively inexpensive price and low maintenance cost, is the direct current rectifier.

It has been found desirable in certain electroplating operations to reverse the polarity of the current going to the electroplating tank. That is, instead of negatively charged current going to the cathode and thus to the piece or object to be plated in the aqueous solution, so that the positive ions in solution are thereby attracted to the cathode, the current is changed so that positively charged current goes to the cathode'and negatively charged current reaches the anode. This reversing of the polarity, which lasts anywhere from a few seconds up to 20 or 30 minutes, depending upon the variables and circumstances of the particularelectroplating situation, electrolytically cleans and microscopically etches the base metal. In this manner the surface to be electroplated, especially in hard chrome plating, can be easily and quickly cleaned and activated. In addition, the polarity may also be reversed to break down any oxide film which frequently forms on certain surfaces. This procedure has sometimes been called an anionic treatmen In order to reverse the polarity when a direct current rectifier is used in an electroplating operation, it is necessary to change the current on the output side of the rectifier. One manner of doing this is simply to switch the leads on the rectifier going to the plating bath, but this has proven to be impractical. It has heretofore been common practice to use a conventional knife switch located in the circuit between the rectifier and the electroplating tank to accomplish such a task. However, numerous problems and difficulties have been encountered with the above described knife switch usage, particularly when the electroplating operation requires an exceedingly high amperage and low voltage.

The capacity of an individual polarity reversing switch can be measured by the cross-sectional area of electrical conducting material incorporated therein. It can thus be seen that when 10,000 amperes or more is used, a large amount of cross-sectional area is necessitated. A knife switch of this magnitude is extremely bulky and cumbersome to operate and can only be handled efficiently when a commercial hydraulic operated device or the like is ateificient in operation.

The primary object of this invention is to provide a new and improved polarity reversing switch.

for usage under very high amperage conditions and still capable of being operated easily by hand.

A further object "of the invention is to provide a polarity reversing switch which has contact cutoff means for automatically separating the contacting areas without having any sliding metal on metal contact as the polarity is being reversed.

Other features, objects and advantages of the present invention will be apparent from the following description of a preferred embodiment illustrated in the accompanying drawing in which:

FIGURE 1 is an isometric view of a polarity reversing switch embodying the invention therein;

FIGURE 2 is a top plan view partially in section illustrating the polarity reversing switch in one circuit forming position;

FIGURE 3 is a top plan view partially in section illus trating the polarity reversing switch in a different circuit forming position with the movement of the connecting member of the movable member shown in dotted outline;

FIGURE 4 is a sectional view taken substantially as indicated along line 4-4 of FIGURE 2 showing the terminals and terminal engaging conductors in contacting position;

FIGURE 5 is a sectional view taken substantially as in+ dicated along line 5-5 of FIGURE 2; and

FIGURE 6 is a sectional view taken substantially as indicated along line 6-6 of FIGURE 3 showing the terminals and terminal engaging conductors in disengaging position.

In accordance with the present invention, a polarity reversing switch is provided with a stationary member having four external terminals and a movable member having internal terminal engaging conductors operable in a first position to form a circuit between pairs of terminals and when in a second position to form a circuit between different pairs of terminals. The terminals are connected to bus bars leading to an electroplating tank so that the flow of direct current through the switch is reversed when the position of the movable member is changed from the first position to the second position. Contact pressure forming means are provided for selectively engaging and disengaging the members in circuit forming positions and contact cutoff means are provided for automatically separating the members when the contact pressure forming means are in a disengaging position.

Referring particularly to FIGURES 1, 2 and 4, a polarity reversing switch, generally designated 10, is illustrated which is intended for use in many industrial operations, as, for example, in electrolytic processes and in particular in the electroplating industry. The polarity reversing switch 10 is provided with a stationary member 11 and a twopiece movable member 12 having one piece on each side of stationary member 11 and being joined together by connecting member 13. As seen in FIGURE 4, one piece of movable member 12 is superjacent stationary member 11 and the other piece of movable member 12 is subjacent stationary member 11. Both the stationary member 11 and the movable member 12 are constructed of a rigid, structurally secure non-conducting material such as wood or plastic or the like.

The stationary member 11 has connected to it by suitable means such as rivets or other appropriate hardware a plurality of external terminals 14. The terminals 14 are situated in diagonal pairs on each side of stationary member 11 with one pair of diagonal terminals 14 connected by means of bus bars (not shown) to .a direct current power source and labeled for convenience and and the other pair of diagonal terminals 14 connected by means of bus bars (not shown) to an electroplating tank and labeled for convenience Tc for the cathode or negative portion of the tank and Ta for the anode or positive portion of the tank. The terminals 14 are preferably constructed of copper or its alloys or aluminum.

The mova'ble member 12 has connected to it on the inner side of each piece of the movable member by bolts 15 or other appropriate hardware a plurality of internal terminal engaging conductors 16. The terminal engaging conductors, as will be described in detail hereinafter, form a circuit between different diagonal terminals and are constructed of a highly conductive metal like copper or its alloys or aluminum. The internal terminal engaging conductors 16 do not have to be constructed of the same material as the external terminals 14 for satisfactory operation.

A shaft 17 passes through movable member 12 and stationary member 11 and is secured to one piece of the movable member 12 by locking member 18. A wing-nut or similar pressure forming member 19 rotatably engages the threaded portion of shaft 17 and can be rotated to selectively engage and disengage the movable member 12 and the stationary member 11 in circuit forming positions. Washers 20 are provided on the shaft 17 at each outer side of movable member 12.

Contact cutoff means are provided in the form of tension springs 21 which encircle the shaft 17 between each piece of the movable member 12 and the stationary member 11. The tension springs 21 automatically -separate the movable member from the stationary member and thus the external terminals from the internal terminal engaging conductors when the pressure forming member 19 is in a disengaging position, see FIGURE 6, by pushing the movable member 12 away from the stationary member 11.

In actual operation, bus bars from a direct current rectifier are connected to terminals 14 labeled and Bus bars connected to terminals 14 labeled To and Ta lead to an electroplating tank. The normal position for the polarity reversing switch during an electroplating operation is illustrated in FIGURE 2. Here, the negative current goes from terminal through terminal engaging conductor 16 to the tank cathode and the positive current goes from terminal through terminal engaging conductor 16 to the tank anode. Thus, the positive ions in solution are attracted to the negative tank cathode where they are electroplated on the desired object which is suspended in solution from the tank cathode. The pressure forming member 19 is rotated toward the locking member 18 until sufiicient pressure is applied to the movable member 12 to ensure that the terminals 14 and terminal engaging conductors 16 are in pressed metal to metal contact. -As seen in FIGURES 2 and 5, the terminal engaging conductors or electrical current conducting metallic strips are rectangular in shape and extend the entire length of one side of the movable member 12.

To change the arrangement of the switch to the second position and thus reverse the polarity it is first necessary to shut off the power supply and then rotate the pressure forming member 19 to a place near the end of the shaft 17. This allows the springs 21 to push the movable member 12 away from the stationary member 11 and thereby automatically separate the terminal engaging conductors 16 from the terminals 14. In addition, there is no metal on metal grinding or scratching when the movable member 12 is rotated by hand by means of connecting member 13 to the position shown in FIGURE 3. The pressure forming member 19 is then again rotated back to its pressure position and the power supply is turned on. The terminal engaging conductors 16 are now arranged so that positive current flows to the tank cathode and negative current flows to the tank anode.

The polarity reversing switch of this invention can be positioned either vertical or horizontal relative to the tank base, although the usual operating position is vertical to the base and floor. In either position, the polarity reversing switch, whether of small design or large, depending upon the amperage, provides an easy, efiicient and inexpensive way to reverse the polarity of direct current.

As a further advantage of the design and construction of the polarity reversing switch, it can be seen that by having metal to metal contact on both sides of stationary member 11, reliability of the switch is greatly increased because damage to a terminal engaging conductor on one side will not render the switch inoperative.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, for some 'rnodifications will be obvious to those skilled in the art.

We claim as our invention:

1. A high amperage polarity reversing switch mounted on a base for reversing current to an electromechanical tank, comprising: a stationary member having two pairs of external terminals, a movable member having internal terminal engaging conductors operable in a first position to form a circuit between pairs of said terminals and when in a second position to form a circuit between different pairs of said terminals, and contact engaging means axially aligned relative to said base for selectively engaging and disengaging said members in circuit forming positions, whereby the flow of current through said switch is reversed when the position of said movable member is changed from said first position to said second position.

2. The polarity reversing switch of claim 1 wherein the contact engaging means are a threaded shaft and a corresponding member engaging said threaded shaft and capable of being rotated on said threaded shaft.

3. The polarity reversing switch as specified in claim 1 in which contact cutoff means are provided to automatically separate the movable member from the stationary member when the contact engaging means are in a disengaging position.

4. The polarity reversing switch as specified in claim 3 in which the contact cutoff means encircle portions of the contact engaging means.

5. A polarity reversing switch mounted on a base, comprising: a stationary member having two pairs of diagonally situated terminals with one pair of diagonal terminals connected to a direct current power source and the other pair of diagonal terminals connected to an electroplating tank, a movable member having terminal engaging conductors operable in a first position to form a circuit between each tank terminal and a power source terminal and when in a second position to form a circuit between each tank terminal and a different power source terminal, and contact engaging means axially aligned relative to said base for selectively engaging and disengaging said members in circuit forming positions, whereby the flow of direct current through said switch to said electroplating tank is reversed when the position of said movable member is changed from said first position to said second position.

6. A polarity reversing switch mounted on a base, comprising: a stationary member having two pairs of diagonally situated terminals with one pair of diagonal terminals connected to a direct current power source and the other pair of diagonal terminals connected to an electroplating tank, a movable member having terminal engaging conductors operable in a first position to form a circuit between each tank terminal and a power source terminal and when in a second position to form a circuit between each tank terminal and a different power source terminal, a shaft positioned in the center of said base and passing through said members connected to said movable member at one end and threaded at the other end, a pressure forming member rotatably engaging said threaded shaft end for selectively engaging and disengaging said members in circuit forming positions, and contact cutoff means to automatically separate the terminal engaging conductors from the terminals when said pressure forming member is in a disengaging position, whereby the flow of direct current through said switch to said electroplating tank is reversed when the position of Said movable member is changed from said first position to said second position.

7. The polarity reversing switch of claim 6 wherein the contact cutofi means are tension springs which push the movable member away from the stationary member.

8. A high amperage polarity reversing switch mounted on a base for-reversing current to an electrochemical tank comprising: a stationary member having two pairs of terminals on each side thereof, a-two-piece movable member having one piece on each side of said stationary member and terminal engaging conductors on the inner side of each piece operable in a first position to form a circuit between pairs of said terminals and when in a second position to form a circuit between dilferent pairs of said terminals, whereby said terminals and terminal engaging conductors contact each other on both sides of said stationary member and the flow of current through said switch is reversed when the position of said movable member is changed from said first position to said second position.

References Cited by the Examiner UNITED STATES PATENTS 8/1902 Moskowitz 2001 6/1928 Laird 200-158 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 0 "5, 265, 846 August 9, 1966 Hans Brechtel et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 19, for "electromechanical" read electrochemical "a Signed and sealed this 22nd day of August 1967.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents 

1. A HIGH AMPERAGE POLARITY REVERSING SWITCH MOUNTED ON A BASE FOR REVERSING CURRENT TO AN ELECTROMECHANICAL TANK, COMPRISING: A STATIONARY MEMBER HAVING TWO PAIRS OF EXTERNAL TERMINALS, A MOVABLE MEMBER HAVING INTERNAL TERMINAL ENGAGING CONDUCTORS OPERABLE IN A FIRST POSITION TO FORM A CIRCUIT BETWEEN PAIRS OF SAID TERMINALS AND WHEN IN A SECOND POSITION TO FORM A CIRCUIT BETWEEN DIFFERENT PAIRS OF SAID TERMINALS, AND CONTACT ENGAING MEANS AXIALLY ALIGNED RELATIVE TO SAID BASE FOR SELECTIVELY ENGAGING AND DISENGAGING SAID MEMBERS IN CIRCUIT FORMING POSITIONS, WHEREBY THE FLOW OF CURRENT THROUGH SAID SWITCH IS REVERSED WHEN THE POSITION OF SAID MOVABLE MEMBER IS CHANGED FROM SAID FIRST POSITION TO SAID SECOND POSITION. 